docs: def _seconds_str(self):
          """
          Returns:
              str: human readable text
  
          Example:
              >>> self = Timerit(num=100, bestof=10, verbose=0)
              >>> self.call(lambda : sum(range(100)))
              >>> print(self._seconds_str())
              ... 'best=3.423 µs, ave=3.451 ± 0.027 µs'
          """
          mean = self.mean()
          unit, mag = _choose_unit(mean, self.unit, self._asciimode)
  
          unit_min = self.min() / mag
          unit_mean = mean / mag
  
          # Is showing the std useful? It probably doesn't hurt.
          std = self.std()
          unit_std = std / mag
          pm = _trychar('±', '+-', self._asciimode)
          fmtstr = ('best={min:.{pr1}{t}} {unit}, '
                    'mean={mean:.{pr1}{t}} {pm} {std:.{pr2}{t}} {unit}')
          pr1 = pr2 = self._precision
          if isinstance(self._precision, int):  # pragma: nobranch
              pr2 = max(self._precision - 2, 1)
          unit_str = fmtstr.format(min=unit_min, unit=unit, mean=unit_mean,
                                   t=self._precision_type, pm=pm, std=unit_std,
                                   pr1=pr1, pr2=pr2)
          return unit_str